Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
A typical image forming apparatus reads a color image on an original document to print not only the color image but also a monochrome image, which is preferred in terms of cost reduction. When the monochrome image is printed from the color image on the original document, color image data is converted into monochrome image data. The conversion into the monochrome image data converts RGB information (R: red, G: green, B: blue) into single-color-grayscale information. This causes information on hue and saturation to be lost. Thus, when a print density difference between adjacent regions is small, it is difficult to distinguish a boundary between the adjacent regions in the printed image.
On the other hand, visibility of a printed matter after the monochrome conversion is different for each user, and the users have respective preferences. Thus, the obtained printed matter may be a printed matter different from an image intended by the user. To solve such problem, for example, there is proposed a technique that performs a preview display of a plurality of pieces of alternative image data having different print densities of two adjacent regions in a monochrome image on an operation panel to enable the user to select the alternative image data.